Underscored by its geographical location, the U.S. relies heavily on ships to secure the trade flows between itself and its partners. Nearly 69 percent of all the goods traded by the U.S. are transported via waterways, predominantly by seagoing vessels.
The MTS supports $4.6 trillion of economic activity each year and accounts for the employment of more than 23 million Americans.
That document does not support the UN Navy involvement in CENTOM. That is a different mission statement. The US Navy asserts: "The United States is a maritime nation, and the U.S. Navy protects America at sea."
So the question remains. "What was being shipped, from what country and to what country?"
Some answers could be 1) "we are the world's policeman," 2) "we're paying for other nation's ships and cargo when they are not paying," or perhaps 3) perhaps the cargo was "American?" I suspect the last is not the answer.
What seems likely, unless you have citations to suggest this incorrect, is that the "Maersk Hangzhou, a Singapore-flagged, Denmark-owned and -operated container ship" might not be fully funding the protection of their business enterprise.
The article does not mention what the cargo was, nor its origin and destination. If not the US, and if we are funding the large share of the policing, there is a significant imbalance in the world, given the US' $34,000,000,000,000+ national debt.
But the US Coast Guard statement does not address this at all.